University of Wisconsin

Space Astronomy Laboratory

ASTRO - 2

WUPPE

OBJECT: 48 Librae (48LIB)
Other Names: HD142983
ID # 2222

UW Astronomer: Karen Bjorkman


48 Librae, a Be star also known as FX Librae, is in the constellation of Libra (the scales), a faint constellation in a sparsely populated region just northwest of the summer constellation of Scorpius. It is about 4 times larger than the Sun, 3 times as hot, and 800 times as bright. It is thought to have a gaseous, disk-like shell of material, which is unstable and changing, around it. It varies in brightness and polarization and is known to be brighter than expected in the infrared.

48-Lib is an intermediate spectral type, has a large v sin i (rotating at about 80% of breakup), and offers a reasonable chance of detecting gravity darkening effects. Since it provides the highest v sin i case, it allows us to look at the effects of iron (Fe) line depolarization.